Process for the bulk-dyeing of linear polyesters

ABSTRACT

Process for bulk-dyeing linear polyesters, characterized in that mixtures consisting of at least two dioxazine dyestuffs, which differ in respect of the nature and/or position of their substituents, are used. Dyeings of improved purity, depth and rub resistance are obtained.

United States Patent [191 Pugin et al.

[ 1 Dec. 30, 1975 PROCESS FOR THE BULK-DYEING OF LINEAR POLYESTERS Inventors: Andre Pugin, Riehen; Kurt Burdeska, Basel; Jost von der Crone, Riehen, all of Switzerland Assignee: Ciba-Geigy Corporation, Ardsley,

Filed: Nov. 8, 1973 Appl. No.: 414,018

Foreign Application Priority Data Nov. 10, 1972 Switzerland 16399/72 U.S. Cl. 26'0/40 P coax 5/29 Field of Search 260/40 P, 246

References Cited UNITED STATES PATENTS 10/1951 Waters et al. 260/40 P 3,635,963 1/1972 I-Iari et al. 260/246 R FOREIGN PATENTS OR APPLICATIONS 2,157,519 5/1972 Germany 739,975 8/1966 Canada 260/246 R OTHER PUBLICATIONS Newland et al., Def. Pub. T883028, published 2-2- 3-71.

Primary ExaminerDonald E. Czaja Assistant Examiner-S. M. Person Attorney, Agent, or FirmVincent J Cavalieri 57 ABSTRACT 11 Claims, No Drawings PROCESS FOR THE BULK-DYEING OF LINEAR POLYESTERS The present invention relates to a process for the bulk-dyeing of linear polyesters with mixtures consisting of at-least two dioxazine dyestuffs which differ in respect of the nature and/or position of their substituents.

Mixtures of particular interest are those'containing at least two dyestuffs of the formula It is also possible to use mixtures which contain both dyestuffs of the formulae (I) and (II) and dyestuffs of the formula (III), or mixtures which in addition to dyestuffs of the formulae (1), (II) or (III) also contain dioxazine dyestuffs of a different structure.

Preferred mixtures are binary mixtures of the dyestuffs to be used, especially those containing 20 80 parts of the dyestuff A and 80 20 parts of the dyestuff B, and above all those containing 60 parts of the dyestuff A and 60 40 parts of the dyestuff B, or ternary mixtures containing approximately equal parts of the dyestuffs A, B and C.

In the dyestuffs of the formula (II), the R,Oradicals are preferably in the m-position to the oxygen atom or nitrogen atom of the oxazine ring and preferably contain l 12 carbon atoms.

As examples, there may be mentioned methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert.- butoxy, amyloxy, hexyloxy, octyloxy, decyloxy or dodecyloxy groups. As examples of hydroxyalkoxy groups, B-hydroxyethoxy, 'y-hydroxypropoxy or 6- (II) R10 @m \m 0R1 wherein R denotes an aliphatic, alicyclic, araliphatic, aromatic or heterocyclic radical, especially an alkyl or hydroxyalkyl group or an aryloxyalkyl, alkoxyalkyl, acyloxyalkyl, cycloalkyl, aralkyl or aryl group, and X denotes a hydrogen or halogen atom or the radical R,O-.

In the above formula (II), R preferably denotes an alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl or acyloxyalkyl group containing 1 6 carbon atoms, a phenalkyl or phenoxyalkyl group of which the alkyl radicals possess l 4 carbon atoms and which can be substituted in the phenyl radical by halogen atoms, or alkyl or alkoxy groups containing 1 4 carbon atoms, a phenyl group which can be substituted by halogen atoms or alkyl or alkoxy groups containing 1 4 carbon atoms, or a naphthyl group, and X has the indicated meaning,

Further preferred mixtures are those containing at least two dyestuffs of the formula NHCOR U cl RCOHN hydroxybutoxy groups may be mentioned. Amongst the series of the alkoxyalkoxy groups, the B-methoxyethoxy, B-ethoxyethoxy or B-hydroxyethoxyethoxy groups may be mentioned. Radicals derived from polyglycols can also be present. As acyloxyalkoxy groups, B-acetoxyethoxy, B-propoxyethoxy, B-isopropoxyethoxy or B-benzoyloxyethoxy groups may be mentioned. The B-phenoxyethoxy group may be mentioned as an example of an aryloxyalkoxy group and benzyloxy and aor B-phenylethoxy groups may be mentioned as phenalkoxy groups. Amongst the series of the aryloxy groups, phenoxy, 0- or p-chlorophenoxy, 2,4-dichlorophenoxy, 2,5-dichlorophenoxy, 2,4,5-trichlorophenoxy, 0- or p-methylphenoxy, 2,4- or 2,6-dimethylphenoxy, 2,4,6-trimethylphenoxy, p-tert.-butylphenoxy, p-amylphenoxy, o-, mor p-methoxyphenoxy, p-phenylphenoxy, p-phenoxyphenoxy, B- naphthoxy, 2-(5,6,7,8-tetrahydro)-naphthoxy or 1- (III) (1,2,3,4-tetrahydro)-naphthoxy groups may be mentioned. Finally, hydroxyl groups etherified by heterocyclic radicals, for example the tetrahydrofurfuryloxy group, should also be mentioned.

3 Some examples of dyestuffs of the formula (I) are listed below: 2,6-dimethoxy-9,lO-dichloro-triphendioxazine, 4,8-dimethoxy-9,l-dichloro-triphendioxazine, 3 ,7-dimethoxy9, l O-dichloro-triphendioxazine, 1,5- dimethoXy-9,lO-dichloro-triphendioxazine, 2,6-diethoxy-9, l O-dichloro-triphendioxazine, 2,6-dipropoxy- 9, l O-dichloro-triphendioxazine, 2,6-diisopropoxy- 9,l0-dichloro-triphendioxazine, 2,6-di-(B-hydroxyethoxy)-9,10dichloro-triphendioxazine, 2,6-di-(B- ethoxyethoxy)-9, l O-dichloro-triphendioxazine, 2,6-di- I fi-propoxyethoxy )-9 l 0-dichloro-triphendioxazine, 2,6-di-( B-acetoxyethoxy)-9, l O-dichloro-triphendioxazine, 2,6-di-(B-phenoxyethoxy )9, l O-dichloro-triphen- :lioxazine, 2,6-di-[B-(p-chlorophenoxy)-ethoxy]-9,l0- iichloro-triphendioxazine, 2 ,6-dibenzyloxy-9 l 0- iichloro-triphendioxazine, 2,6-di-(B-phenethoxy)- J,lO-dichloro-triphendioxazine, 2,6-di-[B-(p-chloro- )henylethoxy)]-9, l 0-dichloro-triphendioxazine, 2,6- li-(B-cyanoethoxy)-9 ,10-dichloro-triphendioxazine, Z,6-di-(a-tetrahydrofuryloxy)-9,10-dichloro-triphendi- )xazine, 2,6-diphenoxy-9 ,1 O-dichloro-triphendioxa- Line, 2,6-di-(o-chlorophenoxy)-9,lO-dichloro-triphenlioxazine, 2,6-di-(p-chlorphenoxy)-9,lO-dichloro-tri- )hendioxazine, 2,6-di-(2',4'4-dichlorophenoxy)-9,l0- lichloro-triphendioxazine, 2,6-di-(2,4',6'-trichloro- )henoxy)-9,lO-dichloro-triphendioxazine, 2,6-di-(onethylphenoxy)-9,10-dichloro-triphendioxazine, 2,6- li-( p-methylphenoxy)-9 l O-dichloro-triphendioxazine, l,6-di-( 2 ',4'-dimethylphenoxy)-9, 1 O-dichloro-triphenlioxazine, 2,6-di-( 2 ,6'-dimethylphenoxy)-9,10- lichloro-triphendioxazine, 2,6-di-(2',4',6'-trimethylhenoxy)-9,lO-dichloro-triphendioxazine, 2,6-di-(pert.-butylphenoxy)-9, l O-dichloro-triphendioxazine, ,6-di-(B-amylphenoxy )-9, l O-dichloro-triphendioxaine, 2,6-di-(p-diphenyloxy)-9,lO-dichloro-triphendixazine, 2 ,6-di-(p-phenoxyphenoxy)-9 ,10-dichloro-trihendioxazine, 2,6-di-( 3 -methoxyphenoxy)-9, l 0- ichloro-triphendioxazine, 2,6-di-(4'-methoxyphenox- )-9,l0-dichloro-triphendioxazine, 2,6-di-(4-methylulphonylphenoxy)-9,l O-dichloro-triphendioxazine, ,6-di-(Bnaphthoxy )-9 l O-dichloro-triphendioxazine, ,6-di-[2-(5',6',7,8'-tetrahydro)-naphthoxy]-9,10- ichloro-triphendioxazine, 2,6-di-[ l l ,2',3 ,4-tetahydro)-naphthoxy]-9,10-dichloro-triphendioxazine, ,6-dimethoxy-l ,5 ,9 l O-tetrachloro-triphendioxazine, ,6-diethoxy-l ,5 ,9, l 0-tetrachloro-triphendioxazine, ,6-dibenzyloxy-l ,5,9, 1 0-tetrachloro-triphendioxaine, 2,6-diphenoxy-l ,5,9,10-tetrachloro-triphendioxaine, 2,6-dimethoxy--l ,5-dibromo-9, 1 O-dichloro-trihendioxazine, 2,6-diphenoxy-l ,5 -dibromo-9, l 0- ichloro-triphendioxazine, 2,6-di-(p-chlorophenoxy)- ,5,9,lO-tetrachloro-triphendioxazine, 2,6-dimethoxy- ,7,9,10-tetrachloro-triphendioxazine, 2,6-diphenoxy- ,7 ,9 ,1 O-tetrachloro-triphendioxazine, 2,6-di-(phlorophenoxy )-3 ,7 ,9, l 0-tetrachloro-triphendioxa- .ne, 2,6-di-(2',4,5 -trichlorophenoxy)-3 ,7,9, l O-tetrahloro-triphendioxazine, 2,6-diphenoxy-3,7-dibromo- ,lO-dichloro-triphendioxazine, 3 ,7 -dimethoxy- ,6,9, l O-tetrachloro-triphendioxazine, 3 ,7-diethoxy- ,6,9, l O-tetrachloro-triphendioxazine, 1 ,2,5 ,6-tettmethoxy-9,lO-dichloro-triphendioxazine, 2,6,3,7-tettmethoxy-l ,5 ,9,10-tetrachloro-triphendioxazine, 2,6- imethoxy-l ,5-dicyano-9, l O-dichloro-triphendioxane, 2,6-dimethoxy-1,5-di-(methylsulphonyl)-9,l0- ichloro-triphendioxazine, 2,6-di-(p-methylsulphonylhenoxy)-1,5,9,l0-tetrachloro-triphendioxazine, 2,6- ibenzoyl-9 ,10-dichloro-triphendioxazine, 2,6-dimeloxy-9 l O-dibenzoyl-triphendioxazine, 2,6-

diphenoxy-9, l O-dibenzoyl-triphendioxazine, 2,6-dimethoxy-9,10-di(methoxycarbonyl)triphendioxazine, 2,6- diethoxy-9, l O-di(methoxycarbonyl )triphendioxazine, 2,6-diphenyl-9, l O-dichloro-triphendioxazine, 2,6-di- (p-chlorophenyl)-9, l O-dichloro-triphendioxazine, 2,6- diphenoxy-9, l O-dimethoxy-triphendioxazine, 2 ,6- dimethoxy-9, l O-diphenoxy-triphendioxazine, 2 ,6- dimethoxy-9, l O-dimethylmercapto-triphendioxazine 2,6-dimethoxy-9, l O-diphenylmercapto-triphendioxazine, 2,6,9,lO-tetraphenoxv-triphendioxazine and 2,6- di (phenylmercapto)-9 ,10-dichloro-triphendioxazine.

In the dyestuffs of the formula (III), R represents, for example, a phenyl group optionally substituted by halogen atoms or alkyl or alkoxy groups containing 1 6 carbon atoms, a benzyl group or especially an alkyl group containing 1 20 carbon atoms.

As examples there may be mentioned: 2,6- diacetylamino-3 ,7,9,10-tetrachloro-triphendioxazine,

2 ,6-diacetylamino-3 ,7-dichloro-9, l O-dibromo-triphendioxazine, 2,6-dipropionylamino-3 ,7,9, l O-tetrachlorotriphendioxazine, 2,6-dibutyrylamino-3,7,9,lO-tetrachloro-triphendioxazine, 2,6-dibenzoylamino-3 ,7,9,10- tetrachloro-triphendioxazine, 2,6-diphenallylamino- 3,7,9,lO-tetrachloro-triphendioxazine, 2,6-di-(4'- chlorobenzoylamino)-3 ,7 ,9, l O-tetrachloro-triphendioxazine and 2,6-distearylamino-3,7,9,lO-tetrachlorotriphendioxazine.

The dioxazines mentioned are in most cases known compounds which can be manufactured according to the customary processes.

As linear polyesters there may be mentioned especially those obtained by polycondensation of terephthalic acid or its esters with glycols of the formula l-lO(Cl-I ),,Ol-l, wherein n denotes the number 2 10, or with l,4-di(hydroxymethyl)-cyclohexane or by polycondensation of glycol ethers of hydroxybenzoic acids, for example p-(B-hydroxyethoxy)-benzoic acid. The term linear polyesters also encompasses copolyesters which are obtained by partial replacement of the terephthalic acid by another dicarboxylic acid or a hydroxycarboxylic acid and/or by partial replacement of the glycol by another diol.

However, the polyethylene terephthalates are of particular interest.

The linear polyesters, especially polyethylene terephthalates, which are to be dyed are intimately mixed, appropriately in the form of powders, chips or granules, with the dyestuff. This can be effected, for example, by sprinkling the polyester particles with the finely divided dry dyestuff powder or by treating the polyester particles with a solution of the dyestuff in an organic solvent and subsequently removing the solvent. lnstead of the pure dyestuffs it is also possible to use dyestuff preparations, for example preparations containing an ethylhydroxyethylcellulose or a polyterpene resin in addition to the dyestuff. Finally, the dyestuff can also be added directly to the fused polyester or before or during the polycondensation of the polyethylene terephthalate.

The ratio of dyestuff to polyester can vary within wide limits depending on the desired depth of colour. In general it is advisable to use from 0.01 to 2 parts of dyestuff per parts of polyester.

The polyester particles treated in this way are fused in an extruder by known processes and extruded to form various articles, especially films or fibres, or cast to form sheets.

Purer and deeper dyeings are obtained with the mix- 120C. The granulestreated in this way are spun by the tures according to the invention than with the individmelt spinning process at 250 275C. ual dyestuffs. The dyed fibres obtained with the mix- The above dyestuff mixture gives red fibres which are tures according to the invention are furthermore distinofa purerand deeper colour than those obtained using guishcd by substantially better rub resistance espe- 5 5 parts of either of the individual components of the cially after thermofixing. dyestuffniiX'tur'e. Furthermore, the change which has In the examples, the parts, unless otherwise stated, occurred, and-ithe rub resistance, of the dyeings which denote parts by weight and the percentages denote have been'thermofixed for30 seconds at 210C (or percentages by weight. thermofixed for 30 seconds at 2l()C and then post- EXAMPLE 1 fixed for 30 minutes at 135 C) are much better in the case of the fibres which have been dyed with the dyel ,000 parts of polyethylene terephthalate.granules.v stuff. mixture than in the case of the fibres dyed with the and 1 part of triethylphosphite are thoroughly mixed in individual components. a mixing drum. After adding 25 parts of the dyestuff Tables l-Ill below list a series of dioxazine dyestuffs No. 1 from Table l below and 2.5 parts of dyestuff No. which are constituents of the mixtures used in Example 6 from Table 1 below, the batch is mixed for a further 2 .4 5. I i minutes and then dried for 10 12 hours in vacuo at Table I Cl R 0 R Cl H i No. R, R n

1 Cl OCH H 2 H 2-Methylphenoxy H 3 H Cl -i 4 n H H OCH h N 5 H QCzH5 i H 6 H -OCH Cl 7 i l H 5 OCH H i 8 H jOCH CH,OCH Cl 9 H H zHs '10 H {Phenoxy H ll Cl "OC O H 12 Br f -OCH? H t 13 H fOCH,CH '-CH;, H 14 H lsopropoxy H l5 H -O-.-CH CH ,OCH H l6 H Benzyloxy H 5 "l7 H ,B-Phenoxyetho xy 1 H l8. i vH OCH CH OH H 19 H 0CH CH -OCOCH H 20 I Cl OCH CH OCH CH CH H A .21 H 2-Methylphenoxy 1 Cl 22. H -2-Methoxyphenoxy Cl 23 Cl 4-Methylsulphonylphenoxy H M 24 Br 2.4.5-Triehlorophenoxy H 25 H 4-Phenylphenoxy OCH 26 H 4-Phenoxyphenoxy OC H 27 H fl-Naphthoxy OCH 28 H 2.6-Dimethylphenoxy OCH CH,OH 29 H 4-Chlorophenoxy OCH 30 H 4-Amylphenoxy OC H 3l H 4-Methoxyphenoxy OCH CH CH 32 H 2,4-Dimethylphenoxy OCH 33 H 2-Tetrahydrofuryl H 34 OCH H 4 H 35 CN OCH H 36 Cl OCH OCH 37 SO CH OCH H 38 H a-( l,2 3,4-Tetrahydro)-naphthoxy H 39 H 4-Phenylphenoxy Cl 40 H OC H CF;, 41 H Phenoxy- CF; 42 H Z-see.-Butyl-4-tert.-butylphenoxy' H 43 H 2 Cl 44 4-Chlorophenyl-mercapto OCH; 45 H Cl OC H 46 H OC H Cl 47 Cl. 4 Cl 1 H v 48 Cl H Cl 2 49 Cl 0C H,CH OisoC H H L 50 H OCH CH OC H Cl 51: Cl ,1 OCH CH OC H H 52 H OCH,CH OC H y H 1 53 H OCH CH OC H H :T able IV-continued Example Parts Dyestuff A Parts Dyestuff B Parts Dyestuff C Shade in polyester No. Table No. Table No. Table 32 2 l ll 2 ll claret 33 2 3 ll 2 8 ll claret 34 2 2 ll 1 6 ll 1 9 II bluishtinged red 35 2 6 III 3 8 III red 36 2.5 4 III 2.5 [0 III bluishtinged red 37 2 9 I11 2 S III claret 38 2.5 4 III 2.5 9 III claret 39 2 3 Ill 3 9 Ill brown 40 2 1 ill 2 2 Ill 2 l4 lll red 4| 2 12 III 1 l6 III 2 17 Ill red 42 2 3 I 2 3 II 2 4 III bluish-tinged red 1 l EXAMPLE 43 the X denote hydrogen or halogen atoms, or wherein If a mixture of 1.25 parts of the dyestuff No. 1, Table I, v i

1.25 parts of the dyestuff No. 3, Table I,

1.25 parts of the dyestuff No. 6, Table 'l and 1.25 parts of the dyestuff No. 7, Table I is used, a bluish-tinged red dyeing is obtained in polyesters.

EXAMPLE 44 If a mixture of 1.5 parts of the dyestuff No. 3, Table I,

1.5 parts of the dyestuff No. 20, Table I,

1.5 parts of the dyestuff No. 10, Table II and 1.5 parts of the dyestuff No. 12, Table III is used, a bluish-tinged red dyeing is obtained in polyesters.

EXAMPLE 45 If a mixture of 5 parts of the dyestuff No. 19, Table 1 and 5 parts of the dyestuff No. 50, Table 1 is used, a red dyeing, which is fast to thermofixing, is obtained in polyesters.

EXAMPLE 46 If a mixture of 5 parts of the dyestuff No. 17, Table l,

5 parts of the dyestuff No. 50, Table 1 and 5 parts of the dyestuff No. 51, Table l is used, a full dyeing, which is fast to thermofixing, is obtained in polyesters.

What we claim is:

1. Process for bulk-dyeing linear polyesters, characterised in that mixtures containing at least 2 dyestuffs of the formula wherein the X denote chlorine or bromine atoms or alkyl, alkoxy, aralkoxy, alkylmercapto, aralkylmercapto, arylmercapto, alkoxycarbonyl or aroyl groups, the Y denote hydrogen atoms or etherified hydroxyl groups, the X denote hydrogen or halogen atoms, etherified hydroxyl groups or trifluoromethyl, aroyl, alkylsulphonyl, phenyl or phenylmercapto groups and the X and, X; form fused benzene rings, are used.

2. Process according to claim 1, characterised in that mixtures containing at least 2 dyestuffs of the formula 3 1 o R 0 mora .l \N x wherein R denotes an aliphatic, alicyclic, araliphatic,

aromatic or heterocyclic radical, especially an alkyl or hydroxyalkyl group or an aryloxyalkyl, alkoxyalkyl, acyloxyalkyl, cycloalkyl, aralkyl or aryl group, and X denotes a hydrogen or halogen atom or the radical R O, are used.

3. Process according to claim 2, characterised in that mixtures containing at least 2 dyestuffs of the indicated formula, wherein R, preferably denotes an alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl or acyloxyalkyl group containing 1 6 carbon atoms, a phenalkyl or phenoxyalkyl group of which the alkyl radicals possess 1 4 carbon atoms and which can be substituted in the phenyl radical by halogen atoms, or alkyl or alkoxy groups containing 1 4 carbon atoms, a phenyl group which can be substituted by halogen atoms or alkyl or alkoxy groups containing 1 4 carbon atoms, or a naphthyl group, and X has the indicated meaning, are used.

4. Process according to claim 1, characterised in that mixtures containing at least two dyestuffs of the formula c1 N on NHCOR wherein the Z denote chlorine or bromine atoms or aryloxy-or alkoxycarbonyl groups and the R denote alkyl, aralkyl or aryl radicals, are used.

5. Process according to claim 4, characterised in that mixtures of dyestuffs of the indicated formula, wherein R denotes an alkyl group containing 1 6 carbon atoms, are used.

6. Process according to claim 1, characterised in that mixtures of dyestuffs of the formula Cl I V 7. Processiaccording to claim 1, characterised in that N O mixtures containing at least two dyestuffs of the for- R 0 0R mula 0 N l 5 3 C1 3 A -OA -O vherein R denotes an aliphatic, alicyclic, araliphatic, 2 tromatic or heterocyclic radical, especially an alkyl or iydroxyalkyl group or an aryloxyalkyl, alkoxyalkyl, tcyloxyalkyl, cycloalkyl, aralkyl or aryl group, and X C]. g f i t ig zg g g z f fii atom or the radical wherein A denotes an alkylene group containing 2 4 I 1 5 C atoms and A denotes an alkyl group containing 1 4 C atoms, a phenyl radical optionally substituted by chlorine atoms, alkyl or alkoxy groups containing 1 6 Cl U NHCOR C atoms, phenoxy or phenyl groups, or an alkanoyl group containing 1 4 C atoms, and X denotes an H or l r l Cl 20 chlorine atom, are used. {(JOHN 8. A process according to claim 1, characterized in Z a that mixtures containing the dyestuffs offthe formulae 6O @OOH CH OCOCH CH COOCHZCH O N and N O Y I O ,0 JH JH OCH CIH CH v CH CH OH OCH Ch O O Q he symbols in the formulae indicated having the mean- 9. A process according to claim 4, characterized in 1g indicated in claim 4, are used. that mixtures containing the dyestuffs of the formulae N O Q 1O OOCH CH O O N and N O on flzCH CH oGH CH CH CH CH CH OCH CH I O N 1 and 3 ,929 ,7 19 t 13 14 10. The dyed linear pol'yeeters obtained according to 11. Dyed linear polyesters containing one of the dyeclaim 1. stuff mixtures defined in claim 2. 

1. PROCESS FOR BULK-DYEING LINEAR POLYESTERS, CHARACTERISED IN THAT MIXTURES CONTAINING AT LEAST 2 DYESTUFFS OF THE FORMULA
 2. Process according to claim 1, characterised in that mixtures containing at least 2 dyestuffs of the formula
 3. Process according to claim 2, characterised in that mixtures containing at least 2 dyestuffs of the indicated formula, wherein R1 preferably denotes an alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl or acyloxyalkyl group containing 1 - 6 carbon atoms, a phenalkyl or phenoxyalkyl group of which the alkyl radicals possess 1 - 4 carbon atoms and which can be substituted in the phenyl raDical by halogen atoms, or alkyl or alkoxy groups containing 1 - 4 carbon atoms, a phenyl group which can be substituted by halogen atoms or alkyl or alkoxy groups containing 1 - 4 carbon atoms, or a naphthyl group, and X3 has the indicated meaning, are used.
 4. Process according to claim 1, characterised in that mixtures containing at least two dyestuffs of the formula
 5. Process according to claim 4, characterised in that mixtures of dyestuffs of the indicated formula, wherein R denotes an alkyl group containing 1 - 6 carbon atoms, are used.
 6. Process according to claim 1, characterised in that mixtures of dyestuffs of the formula
 7. Process according to claim 1, characterised in that mixtures containing at least two dyestuffs of the formula
 8. A process according to claim 1, characterized in that mixtures containing the dyestuffs of the formulae
 9. A process according to claim 4, characterized in that mixtures containing the dyestuffs of the formulae
 10. The dyed linear polyesters obtained according to claim
 1. 11. Dyed linear polyesters containing one of the dyestuff mixtures defined in claim
 2. 